a) Field of the Invention
The present invention relates to both an action mechanism for driving the movable members of a doll imitating a human being or an animal and a method of setting the operational initial position of the action mechanism.
b) Description of the Prior Art
Trials have been made in the prior art to move intrinsically immovable toy dolls or the like mechanically.
The dolls are called the "marionette" in Japan and the "automaton" in U.S.A. and Europe, and most of them perform predetermined motions by driving their necks or hands and feet by using springs or the like as drive sources.
These motions are divided into those imitating daily actions of a human being such as writing a letter or putting on make-up and into dancing actions to music.
The action mechanism for the aforementioned motions uses a drive source such as springs and a mechanism including cams and links to be actuated by the drive source.
Moreover, the action mechanism described above is enabled to perform a variety of dynamic actions if one or more drive motors are used and if the ON/OFF and the rotational direction of those drive motors are controlled by a computer such as a microcomputer.
When a doll or the like is to be moved by using springs as its drive source and by using a cam or link mechanism, its motion patterns are simplified. Therefore, if a plurality of actions are to be performed, it is necessary either to incorporate a complicated mechanism such as a cam or link mechanism or, as the case may be, to incorporate a partial mechanism in an exchangeable manner and to replace it.
Moreover, the action doll, i.e., the so-called "robot doll" using an actuator such as drive motors and a microcomputer for controlling the actuator is accompanied, if articulated in multiplicity or given many degrees of freedom in its movable members, by a problem in that the mechanism becomes complicated, suffers from increased weight and further, is made difficult to move easily.
Even further, when the plurality of movable members are to be controlled by computer, it becomes necessary to detect the absolute positions of the movable members in accordance with the ON/OFF of the control system. Generally speaking, position sensors are provided for the individual movable members, and drive motors are rotated in predetermined directions simultaneously as the power source of the control system is turned on so that the program is reset when the position sensors are operated.
The provision of the movable members with the position sensors makes it necessary to lead signal lines between the doll body and the control circuit disposed outside of the doll, but is adversely affected by the turning structure of the doll body. It is, therefore, conceivable to detect the rotational positions of the individual drive units by detecting the rotational positions of the drive members such as the drive shafts or drive gears which are arranged outside of the doll body for driving the individual movable members.
However, it raises a problem of increasing the number of parts and raising the production cost to provide the plurality of movable member driving members individually with the position sensors.
Still further, when the operational initial position of the actions of the doll or the like is to be set, consistency with the actions commencing subsequent to the setting operation of the initial position is lost which raises a problem that the elaborate actions are ruined if the plurality of movable member should move to their initial positions without any correlation.